The first problem I want to solve was that convert MD file to PDF.

And I found the powerful way was browser print. It allows you zoom rate/choose page range.

So, I dig in CSS media query and try to compatible cross browser(Chrome&FF).

I made an editor in left side just cause sometimes we want edit some typo or something before convert...haha, codemirror makes a good user experience than textarea.

Yeah, that technically works ;)

I was kind of expecting that the PDF generation is done with some script like https://github.com/mrrio/jspdf and then rendered with https://github.com/mozilla/pdf.js :)

Small preference would be for the edits on the left side to be saved in local storage for the next visit similar to dillinger.io

do you know if there is a way to remove the datetime stamp header that is inserted into the pdf when printing?

Once Chrome's print dialog pops up, you can expand "More settings" and then uncheck "Headers and footers".

thanks, worth noting that the print dialog does not support that option when using Firefox on Windows

I think you need to open it in Print Preview to change those settings, which is accessible in the main menu (there's not a keyboard shortcut, unfortunately).